优化数据库结构

backend/shared/models/signin_log.py

@@ -12,7 +12,7 @@ class SigninLog(Base):
     id = Column(Integer, primary_key=True, autoincrement=True)
     account_id = Column(String(36), ForeignKey("accounts.id"), nullable=False)
     topic_title = Column(String(100))
-    status = Column(String(20), nullable=False)
+    status = Column(String(50), nullable=False)
     reward_info = Column(JSON, nullable=True)
     error_message = Column(Text, nullable=True)
     signed_at = Column(DateTime, server_default=func.now())

init-db.sql

@@ -51,7 +51,7 @@ CREATE TABLE IF NOT EXISTS signin_logs (
     id BIGINT AUTO_INCREMENT PRIMARY KEY,
     account_id CHAR(36) NOT NULL,
     topic_title VARCHAR(100),
-    status VARCHAR(20) NOT NULL,
+    status VARCHAR(50) NOT NULL,
     reward_info JSON,
     error_message TEXT,
     signed_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,